Wiki states "Major-General Sir Ernest Dunlop Swinton, KBE, CB, DSO (21 October 1868 - 15 January 1951) was a British Army officer who was active in the development and adoption of the tank during the First World War. He was also a war correspondent and author of several allegorical works of fiction on military themes, including a lastingly influential book on tactics and good practice. He is credited, along with fellow officer Lieutenant-Colonel Walter Dally Jones, with having initiated the use of the word "tank" as a code-name for the first tracked, armoured fighting vehicles."

This item was found in a very large collection of genuine autographs, letters and other ephemera purchased at an auction in Cardiff.